Pre-set torque limiter sub

Abstract

A preset torque limiter sub having a pin member and a box member. The pin member is connected to a section of drill pipe and has a male connection at one end. The box member is connected to a second section of drill pipe. The male connection and the female connection are connected together. Whenever the torque on the sub exceeds a selected amount, the pin member and the box member can rotate with respect to one another. However, whenever the torque on the sub is below the selected amount, the pin member and the box member are held rigidly together.

I claim: 
     
       1. A torque limiter sub, comprising: a box member having a female connection at one end and a makeup shoulder;   a pin member having a male member at one end and a makeup shoulder which contacts the makeup shoulder in the box member;   a selected one of the female connection and the male connection having threads and the other connection having concentric grooves;   a split ring insert, located between the female connection and the male connection, said insert having threads and concentric grooves to mate and mesh with said selected ones of said threads and grooves on the female connection and the male connection to hold the female connection and the male connection against rotation with respect to one another whenever the torque on the sub is below a selected amount, but to allow the female connection and the male connection to rotate with respect to one another, without separating axially, whenever the torque on the sub exceeds the selected amount; and   retention means for holding the insert against rotational movement along the concentric grooves during makeup of the torque limiter sub.   
     
     
       2. A torque limiter sub, comprising: a pin member having connection means at one end for connecting the pin member to a section of drill pipe, a makeup shoulder, and a male connection at the other end, said male connection having concentric grooves around the outer surface;   a box member having connection means at one end for connecting the box member to a section of drill pipe, a makeup shoulder, and a female connection at the other end, said female connection having threads on the inner surface;   a split ring insert, located between the male connection and the female connection, said insert having concentric grooves on the inner surface of the insert to correspond to the grooves on the male connection and having threads on the outer surface of the insert to correspond to the threads on the female connection to hold the female connection and the male connection against rotation with respect to one another whenever the torque on the sub is below a selected amount, but to allow the female connection and the male connection to rotate with respect to one another, without separating axially, whenever the torque on the sub exceeds the selected amount; and   retention means for holding the insert against rotational movement relative to the male connection during makeup of the torque limiter sub.   
     
     
       3. A torque limiter sub, comprising: a pin member having connection means at one end for connecting the pin member to a section of drill pipe, a makeup shoulder, and a male connection at the other end, said male connection having concentric grooves around the outer surface;   a box member having connection means at one end for connecting the box member to a section of drill pipe, a makeup shoulder, and a female connection at the other end, said female connection having threads on the inner surface;   a split ring insert, located between the male connection and the female connection, said insert having concentric grooves on the inner surface of the insert to correspond to the grooves on the male connection and having threads on the outer surface of the insert to correspond to the threads on the female connection to hold the female connection and the male connection against rotation with respect to one another whenever the torque on the sub is below a selected amount, but to allow the female connection and the male connection to rotate with respect to one another, without separating axially, whenever the torque on the sub exceeds the selected amount; and   a shot pin for holding the insert against rotational movement relative to the male connection during makeup of the torque limiter sub.   
     
     
       4. A torque limiter sub, comprising: a pin member having connection means at one end for connecting the pin member to a section of drill pipe, a makeup shoulder, and a male connection at the other end, said male connection having concentric grooves around the outer surface;   a box member having connection means at one end for connecting the box member to a section of drill pipe, a makeup shoulder, and a female connection at the other end, said female connection having threads on the inner surface;   a split ring insert, located between the male connection and the female connection, said insert having concentric grooves on the inner surface of the insert to correspond to the grooves on the male connection and having threads on the outer surface of the insert to correspond to the threads on the female connection to hold the female connection and the male connection against rotation with respect to one another whenever the torque on the sub is below a selected amount, but to allow the female connection and the male connection to rotate with respect to one another, without separating axially, whenever the torque on the sub exceeds the selected amount; and   a plurality of removable shot pins, inserted through holes in the pin member into the split ring insert, for holding the insert against rotational movement relative to the male connection during makeup of the torque limiter sub.   
     
     
       5. A torque limiter sub, comprising: a pin member having connection means at one end for connecting the pin member to a section of drill pipe, a makeup shoulder, and a male connection at the other end, said male connection having concentric grooves around the outer surface;   a box member having connection means at one end for connecting the box member to a section of drill pipe, a makeup shoulder, and a female connection at the other end, said female connection having threads on the inner surface;   a split ring insert, generally in the shape of a hollow frustum, located between the male connection and the female connection, said insert having concentric grooves on the inner surface of the insert to correspond to the grooves on the male connection and having threads on the outer surface of the insert to correspond to the threads on the female connection to hold the female connection and the male connection against rotation with respect to one another whenever the torque on the sub is below a selected amount, but to allow the female connection and the male connection to rotate with respect to one another, without separating axially, whenever the torque on the sub exceeds the selected amount;   a plurality of removable shot pins, inserted through holes in the pin member into the split ring insert, for holding the insert against rotational movement relative to the male connection during makeup of the torque limiter sub, said holes being evenly spaced around the circumference of the pin; and   a plurality of dry seal plugs for sealing the holes in the pin member after the shot pins have been removed.